Leadless packages, such as the Dual Flat No-Lead (DFN) and Quad Flat No-Lead (QFN) package layouts, are built upon an etched or stamped leadframe. The leadframe structure, commonly a metal (e.g., copper) strip, allows the exposed die pads and exposed leads to be locked into place during fabrication. The leadframe structure can be arranged in a step-and-repeat matrix of leadframe cells. Multiple leadless packages can be fabricated upon a leadframe matrix.
Electrically conductive leads are connected to a tie-bar feature to secure them in position. Bond pads can be created from the leads (e.g., the tips of the leads). The IC die is attached to a Die-attach Paddle (DAP) situated in the center of the leadless package, for example using an organic compound (e.g., epoxy). The wire bond pads of the IC die are then connected to the bond pads of the leadless package and wire bonded, for example, using standard wire bonding techniques. Once the die is attached to the leadframe, the package is encapsulated with a mold compound (e.g., plastic, epoxy or ceramic, etc.) and then cured. The cured hardened mold compound forms a rigid structure to hold the leadframe features in position. Individual leadless packages can be singulated from the tie-bar at this point, for example by using a sawing or punching technique.
The conventional DFN packaging solutions described above fail to provide flexible connection options when electrically connecting IC die to a leadframe cell during assembly of the DFN package.